Comment on "Petrographic features influencing basic geotechnical parameters of carbonate soft rocks from Apulia (southern Italy)" [Eng. Geol. 233: 76–97].

This comment discusses a recent paper by Festa et al. (Eng. Geol. 233: 76–97, 2018), in which they illustrate the relationships between fabric features and, basic physical and mechanical parameters of carbonate soft rocks from Apulia by means of a comparison between qualitative information from petrographic analysis in thin sections and quantitative experimental data from laboratory geotechnical tests. In the opinion of the author of this comment, some considerations and clarifications have to be made based on the data presented by Festa et al. (2018) in their paper and, results of new and previous studies on this specific topic published in international journals, scientific books and conference proceedings. • Physical and mechanical behaviour of the Apulian calcarenites is conditioned by syn-depositional and post-depositional diagenesis. • Porosity of these materials is mostly open; coarse-grained rudstones, in which drusy, granular or blocky cement determine the isolation of some pores from the others are an exception. Permeability of the Apulian calcarenites depends above all on pore-size distribution. • Rock weathering as well as stone durability depends on many factors, but other conditions being equal, is closely related to both geometry and topology of the pore network and strength. • The mechanical behaviour of these materials results strongly affected by the presence of water in the pores, with strength and stiffness that significantly decrease in the transition from dry to saturated conditions. • A comparison between qualitative results from petrographic analysis in thin sections and quantitative experimental data from laboratory geotechnical tests can provide useful information if there is a rational approach based on the knowledge of the physical meaning of each geotechnical parameter considered in the study and the main factors of its variability. [ABSTRACT FROM AUTHOR]